In 1605, the Jesuit missionary Matteo Ricci published Xizi Qiji (《西字奇蹟》; Xīzì Qíjī; Hsi-tzu Ch'i-chi; 'Miracle of Western Letters') in Beijing.[8] This was the first book to use the Roman alphabet to write the Chinese language. Twenty years later, another Jesuit in China, Nicolas Trigault, issued his Xi Ru Ermu Zi (《西儒耳目資》; Hsi Ju Erh-mu Tzu; 'Aid to the Eyes and Ears of Western Literati') at Hangzhou.[9] Neither book had much immediate impact on the way in which Chinese thought about their writing system, and the romanizations they described were intended more for Westerners than for the Chinese.[10]

One of the earliest Chinese thinkers to relate Western alphabets to Chinese was late Ming to early Qing dynasty scholar-official, Fang Yizhi (方以智; Fāng Yǐzhì; Fang I-chih; 1611–1671).[11]

The first late Qing reformer to propose that China adopt a system of spelling was Song Shu (1862–1910). A student of the great scholars Yu Yue and Zhang Taiyan, Song had been to Japan and observed the stunning effect of the kana syllabaries and Western learning there. This galvanized him into activity on a number of fronts, one of the most important being reform of the script. While Song did not himself actually create a system for spelling Sinitic languages, his discussion proved fertile and led to a proliferation of schemes for phonetic scripts.[10]

In the early 1930s, Communist Party of China leaders trained in Moscow introduced a phonetic alphabet using Roman letters which had been developed in the Soviet Oriental Institute of Leningrad and was originally intended to improve literacy in the Russian Far East.[13][note 1] This Sin Wenz or "New Writing"[14] was much more linguistically sophisticated than earlier alphabets, but with the major exception that it did not indicate tones of Chinese.[15]

In 1940, several thousand members attended a Border Region Sin Wenz Society convention. Mao Zedong and Zhu De, head of the army, both contributed their calligraphy (in characters) for the masthead of the Sin Wenz Society's new journal. Outside the CCP, other prominent supporters included Dr. Sun Yat-sen's son, Sun Fo; Cai Yuanpei, the country's most prestigious educator; Tao Xingzhi, a leading educational reformer; and Lu Xun. Over thirty journals soon appeared written in Sin Wenz, plus large numbers of translations, biographies (including Lincoln, Franklin, Edison, Ford, and Charlie Chaplin), some contemporary Chinese literature, and a spectrum of textbooks. In 1940, the movement reached an apex when Mao's Border Region Government declared that the Sin Wenz had the same legal status as traditional characters in government and public documents. Many educators and political leaders looked forward to the day when they would be universally accepted and completely replace Chinese characters. Opposition arose, however, because the system was less well adapted to writing regional languages, and therefore would require learning Mandarin. Sin Wenz fell into relative disuse during the following years.[16]

In 1943, the U.S. military engaged Yale University to develop a romanization of Mandarin Chinese for its pilots flying over China. The resulting system is very close to pinyin, but does not use English letters in unfamiliar ways; for example, pinyinx for [ɕ] is written as sy in the Yale system. Medial semivowels are written with y and w (instead of pinyini and u), and apical vowels (syllabic consonants) with r or z. Accent marks are used to indicate tone.

Pinyin was created by Chinese linguists, including Zhou Youguang, as part of a Chinese government project in the 1950s. Zhou is often called "the father of pinyin,"[1][17][18][19] Zhou worked as a banker in New York when he decided to return to China to help rebuild the country after the establishment of the People's Republic of China in 1949. He became an economics professor in Shanghai, and in 1955, when China's Ministry of Education created a Committee for the Reform of the Chinese Written Language, Premier Zhou Enlai assigned Zhou Youguang the task of developing a new romanization system, despite the fact that he was not a professional linguist.[1]

Hanyu Pinyin was based on several existing systems: Gwoyeu Romatzyh of 1928, Latinxua Sin Wenz of 1931, and the diacritic markings from zhuyin (bopomofo).[20] "I'm not the father of pinyin," Zhou said years later; "I'm the son of pinyin. It's [the result of] a long tradition from the later years of the Qing dynasty down to today. But we restudied the problem and revisited it and made it more perfect."[21]

A draft was published on February 12, 1956. The first edition of Hanyu Pinyin was approved and adopted at the Fifth Session of the 1st National People's Congress on February 11, 1958. It was then introduced to primary schools as a way to teach Standard Chinese pronunciation and used to improve the literacy rate among adults.[22]

Beginning in the early 1980s, Western publications addressing Mainland China began using the Hanyu Pinyin romanization system instead of earlier romanization systems;[23] this change followed the normalization of diplomatic relations between the United States and the PRC in 1979.[24] In 2001, the PRC Government issued the National Common Language Law, providing a legal basis for applying pinyin.[22] The current specification of the orthographic rules is laid down in the National Standard GB/T 16159-2012.[25]

The spelling of Chinese geographical or personal names in pinyin has become the most common way to transcribe them in English. Pinyin has also become the dominant method for entering Chinese text into computers in Mainland China, in contrast to Taiwan; where Bopomofo is most commonly used.

A school slogan asking elementary students to speak Standard Chinese is annotated with pinyin, but without tonal marks.

Families outside of Taiwan who speak Mandarin as a mother tongue use pinyin to help children associate characters with spoken words which they already know. Chinese families outside of Taiwan who speak some other language as their mother tongue use the system to teach children Mandarin pronunciation when they learn vocabulary in elementary school.[28][29]

Since 1958, pinyin has been actively used in adult education as well, making it easier for formerly illiterate people to continue with self-study after a short period of pinyin literacy instruction.[30]

Pinyin has become a tool for many foreigners to learn Mandarin pronunciation, and is used to explain both the grammar and spoken Mandarin coupled with Chinese characters (汉字; 漢字; Hànzì). Books containing both Chinese characters and pinyin are often used by foreign learners of Chinese. Pinyin's role in teaching pronunciation to foreigners and children is similar in some respects to furigana-based books (with hiragana letters written above or next to kanji, directly analogous to zhuyin) in Japanese or fully vocalised texts in Arabic ("vocalised Arabic").

The tone-marking diacritics are commonly omitted in popular news stories and even in scholarly works. This results in some degree of ambiguity as to which words are being represented.

In Yiling, Yichang, Hubei, text on road signs appears both in Chinese characters and in Hanyu Pinyin

When a foreign writing system with one set of coding/decoding system is taken to write a language, certain compromises may have to be made. The result is that the decoding systems used in some foreign languages will enable non-native speakers to produce sounds more closely resembling the target language than will the coding/decoding system used by other foreign languages. Native speakers of English will decode pinyin spellings to fairly close approximations of Mandarin except in the case of certain speech sounds that are not ordinarily produced by most native speakers of English: j[tɕ], q[tɕʰ], x[ɕ], z[ts], c[tsʰ], s[s], zh[ʈʂ], ch[ʈʂʰ], sh[ʂ], and r[ɻ] exhibiting the greatest discrepancies.

In this system, the correspondence between the Roman letter and the sound is sometimes idiosyncratic, though not necessarily more so than the way the Latin script is employed in other languages. For example, the aspiration distinction between b, d, g and p, t, k is similar to that of these syllable-initial consonants English (in which the two sets are however also differentiated by voicing), but not to that of French. Letters z and c also have that distinction, pronounced as [ts] and [tsʰ] (whilst reminiscent of both of them being used for the phoneme /ts/ in the German language and Latin script-using Slavic languages respectively). From s, z, c come the digraphssh, zh, ch by analogy with English sh, ch. Although this introduces the novel combination zh, it is internally consistent in how the two series are related, and reminds the trained reader that many Chinese people pronounce sh, zh, ch as s, z, c (and English-speakers use zh to represent /ʒ/ in foreign languages such as Russian anyway). In the x, j, q series, the pinyin use of x is similar to its use in Portuguese, Galician, Catalan, Basque, and Maltese; and the pinyin q is akin to its value in Albanian; both pinyin and Albanian pronunciations may sound similar to the ch to the untrained ear. Pinyin vowels are pronounced in a similar way to vowels in Romance languages.

The pronunciation and spelling of Chinese words are generally given in terms of initials and finals, which represent the segmental phonemic portion of the language, rather than letter by letter. Initials are initial consonants, while finals are all possible combinations of medials (semivowels coming before the vowel), a nucleus vowel, and coda (final vowel or consonant).

Unlike European languages, clusters of letters – initials (声母; 聲母; shēngmǔ) and finals (韵母; 韻母; yùnmǔ) – and not consonant and vowel letters, form the fundamental elements in pinyin (and most other phonetic systems used to describe the Han language). Every Mandarin syllable can be spelled with exactly one initial followed by one final, except for the special syllable er or when a trailing -r is considered part of a syllable (see below, and see erhua). The latter case, though a common practice in some sub-dialects, is rarely used in official publications. One exception is the city Harbin (哈尔滨; 哈爾濱), whose name comes from the Manchu language.

Even though most initials contain a consonant, finals are not always simple vowels, especially in compound finals (复韵母; 複韻母; fùyùnmǔ), i.e. when a "medial" is placed in front of the final. For example, the medials [i] and [u] are pronounced with such tight openings at the beginning of a final that some native Chinese speakers (especially when singing) pronounce yī (衣, clothes, officially pronounced /í/) as /jí/ and wéi (围; 圍, to enclose, officially pronounced /uěi/) as /wěi/ or /wuěi/. Often these medials are treated as separate from the finals rather than as part of them; this convention is followed in the chart of finals below.

1y is pronounced [ɥ] (a labial-palatal approximant) before u.2 The letters w and y are not included in the table of initials in the official pinyin system. They are an orthographic convention for the medials i, u and ü when no initial is present. When i, u, or ü are finals and no initial is present, they are spelled yi, wu, and yu, respectively.

In each cell below, the first line indicates IPA, the second indicates pinyin for a standalone (no-initial) form, and the third indicates pinyin for a combination with an initial. Other than finals modified by an -r, which are omitted, the following is an exhaustive table of all possible finals.1[31]

The only syllable-final consonants in Standard Chinese are -n and -ng, and -r, which are attached as a grammatical suffix. A Chinese syllable ending with any other consonant either is from a non-Mandarin language (a southern Chinese language such as Cantonese, or a minority language of China; possibly reflecting final consonants in Old Chinese), or indicates the use of a non-pinyin romanization system (where final consonants may be used to indicate tones).

Coda

∅

/i/

/u/

/n/

/ŋ/

Medial

∅

[ɨ]

-i

[ɤ]e-e

[a]a-a

[ei̯]ei-ei

[ai̯]ai-ai

[ou̯]ou-ou

[au̯]ao-ao

[ən]en-en

[an]an-an

[ʊŋ]

-ong

[əŋ]eng-eng

[aŋ]ang-ang

/j/

[i]yi-i

[je]ye-ie

[ja]ya-ia

[jou̯]you-iu

[jau̯]yao-iao

[in]yin-in

[jɛn]yan-ian

[jʊŋ]yong-iong

[iŋ]ying-ing

[jaŋ]yang-iang

/w/

[u]wu-u

[wo]wo-uo 3

[wa]wa-ua

[wei̯]wei-ui

[wai̯]wai-uai

[wən]wen-un

[wan]wan-uan

[wəŋ]weng

[waŋ]wang-uang

/y/

[y]yu-ü 2

[ɥe]yue-üe 2

[yn]yun-ün 2

[ɥɛn]yuan-üan 2

1[aɚ̯] is written er. For other finals formed by the suffix -r, pinyin does not use special orthography; one simply appends r to the final that it is added to, without regard for any sound changes that may take place along the way. For information on sound changes related to final r, please see Erhua#Rules.2ü is written as u after j, q, or x.3uo is written as o after b, p, m, f, or w.

Technically, i, u, ü without a following vowel are finals, not medials, and therefore take the tone marks, but they are more concisely displayed as above. In addition, ê[ɛ] (欸; 誒) and syllabic nasals m (呒, 呣), n (嗯, 唔), ng (嗯, 𠮾) are used as interjections.

roughly like the Scotsch. English h as in hay or, more closely in some American dialects, hero is an acceptable approximation. One way to produce this sound is by very slowly making a "k" sound, pausing at the point where there is just restricted air flowing over the back of the tongue (after the release at the beginning of a "k")

No equivalent in English, but similar to an unaspirated "-chy-" sound when said quickly. Like q, but unaspirated. Is similar to the English name of the letter G, but curl the tip of the tongue downwards to stick it at the back of the teeth. Not like the s in vision despite the common English pronunciation of "Beijing". The sequence "ji" word-initially is the same as the Japanese pronunciation of じ(ジ)ji.

No equivalent in English. Like punch yourself, with the lips spread wide as when one says ee. Curl the tip of the tongue downwards to stick it at the back of the teeth and strongly aspirate. The sequence "qi" word-initially is similar to the Japanese pronunciation of ち(チ)chi.

No equivalent in English. Like -sh y-, with the lips spread as when one says ee and with the tip of the tongue curled downwards and stuck to the back of the teeth. The sequence "xi" is similar to the Japanese pronunciation of し(シ)shi.

Y and w are equivalent to the semivowel medials i, u, and ü (see below). They are spelled differently when there is no initial consonant in order to mark a new syllable: fanguan is fan-guan, while fangwan is fang-wan (and equivalent to *fang-uan). With this convention, an apostrophe only needs to be used to mark an initial a, e, or o: Xi'an (two syllables: [ɕi.an]) vs. xian (one syllable: [ɕi̯ɛn]). In addition, y and w are added to fully vocalic i, u, and ü when these occur without an initial consonant, so that they are written yi, wu, and yu. Some Mandarin speakers do pronounce a [j] or [w] sound at the beginning of such words—that is, yi[i] or [ji], wu[u] or [wu], yu[y] or [ɥy],—so this is an intuitive convention. See below for a few finals which are abbreviated after a consonant plus w/u or y/i medial: wen → C+un, wei → C+ui, weng → C+ong, and you → C+iu.

** Note on the apostrophe

The apostrophe (') (隔音符號; géyīn fúhào; 'syllable-dividing mark') is used before a syllable starting with a vowel (a, o, or e) in a multiple-syllable word when the syllable does not start the word (which is most commonly realized as [ɰ]), unless the syllable immediately follows a hyphen or other dash.[33] This usage is done to remove ambiguity that could arise, as in Xi'an, which consists of the two syllables xi ("西") an ("安"), compared to such words as xian ("先"). (This ambiguity does not occur when tone marks are used: the two tone marks in Xīān unambiguously show that the word consists of two syllables. However, even with tone marks, the city is usually spelled with an apostrophe as Xī'ān.)

Pinyin differs from other romanizations in several aspects, such as the following:

Syllables starting with u are written as w in place of u (e.g., *uan is written as wan). Standalone u is written as wu.

Syllables starting with i are written as y in place of i (e.g., *ian is written as yan). Standalone i is written as yi.

Syllables starting with ü are written as yu in place of ü (e.g., *üe is written as yue).

ü is written as u when there is no ambiguity (such as ju, qu, and xu), but written as ü when there are corresponding u syllables (such as lü and nü). In such situations where there are corresponding u syllables, it is often replaced with v on a computer, making it easier to type on a standard keyboard.

When preceded by a consonant, iou, uei, and uen are simplified as iu, ui, and un (which do not represent the actual pronunciation).

As in zhuyin, what are actually pronounced as buo, puo, muo, and fuo are given a separate representation: bo, po, mo, and fo.

The apostrophe (') is used before a syllable starting with a vowel (a, o, or e) in a multiple-syllable word when the syllable does not start the word (which is most commonly realized as [ɰ]), unless the syllable immediately follows a hyphen or other dash.[33] This is done to remove ambiguity that could arise, as in Xi'an, which consists of the two syllables xi (西) an (安), compared to such words as xian (先). (This ambiguity does not occur when tone marks are used: The two tone marks in "Xīān" unambiguously show that the word consists of two syllables. However, even with tone marks, the city is usually spelled with an apostrophe as "Xī'ān".)

Eh alone is written as ê; elsewhere as e. Schwa is always written as e.

zh, ch, and sh can be abbreviated as ẑ, ĉ, and ŝ (z, c, s with a circumflex). However, the shorthands are rarely used due to difficulty of entering them on computers and are confined mainly to Esperanto keyboard layouts. Early drafts and some published material used diacritic hooks below instead: ᶎ (ȥ/ʐ), ꞔ, ʂ (ᶊ).[34]

Early drafts also contained the letter ɥ or ч, borrowed from the Cyrillic script, in place of later j.[34]

The letter v is unused (except in spelling foreign languages, languages of minority nationalities, and some dialects), despite a conscious effort to distribute letters more evenly than in Western languages. However, sometimes, for ease of typing into a computer, the v is used to replace a ü.

Most of the above are used to avoid ambiguity when writing words of more than one syllable in pinyin. For example, uenian is written as wenyan because it is not clear which syllables make up uenian; uen-ian, uen-i-an, and u-en-i-an are all possible combinations whereas wenyan is unambiguous because we, nya, etc. do not exist in pinyin. See the pinyin table article for a summary of possible pinyin syllables (not including tones).

Although Chinese characters represent single syllables, Mandarin Chinese is a polysyllabic language. Spacing in pinyin is usually based on words, and not on single syllables. However, there are often ambiguities in partitioning a word. The Basic Rules of the Chinese Phonetic Alphabet Orthography (汉语拼音正词法基本规则; 漢語拼音正詞法基本規則; Hànyǔ Pīnyīn Zhèngcífǎ Jīběn Guīzé) were put into effect in 1988 by the National Educational Commission (国家教育委员会; 國家教育委員會; Guójiā Jiàoyù Wěiyuánhuì) and the National Language Commission (国家语言文字工作委员会; 國家語言文字工作委員會; Guójiā Yǔyán Wénzì Gōngzuò Wěiyuánhuì).[35] These rules became a Guobiao standard in 1996[35] and were updated in 2012.[36]

General

Single meaning: Words with a single meaning, which are usually set up of two characters (sometimes one, seldom three), are written together and not capitalized: rén (人, person); péngyou (朋友, friend); qiǎokèlì (巧克力, chocolate)

Combined meaning (4 or more characters): Words with four or more characters having one meaning are split up with their original meaning if possible: wúfèng gāngguǎn (无缝钢管; 無縫鋼管, seamless steel-tube); huánjìng bǎohù guīhuà (环境保护规划; 環境保護規劃, environmental protection planning); gāoměngsuānjiǎ (高锰酸钾; 高錳酸鉀, potassium permanganate)

Duplicated words

AA: Duplicated characters (AA) are written together: rénrén (人人, everybody), kànkan (看看, to have a look), niánnián (年年, every year)

Exceptions are words traditionally connected: tiānshang (天上, in the sky or outerspace), dìxia (地下, on the ground), kōngzhōng (空中, in the air), hǎiwài (海外, overseas)

Surnames are separated from the given names, each capitalized: Lǐ Huá (李华; 李華), Zhāng Sān (张三; 張三). If the surname and/or given name consists of two syllables, it should be written as one: Zhūgě Kǒngmíng (诸葛孔明; 諸葛孔明).

Verbs (动词; 動詞; dòngcí): Verbs and their suffixes -zhe (着; 著), -le (了) or -guo ((过; 過) are written as one: kànzhe (看着; 看著, seeing), jìnxíngguo (进行过; 進行過, have been implemented). Le as it appears in the end of a sentence is separated though: Huǒchē dào le. (火车到了; 火車到了, The train [has] arrived).

If verbs and their complements are each monosyllabic, they are written together; if not, they are separated: gǎohuài (搞坏; 搞壞, to make broken), dǎsǐ (打死, hit to death), huàwéi (化为; 化為, to become), zhěnglǐ hǎo (整理好, to sort out), gǎixiě wéi (改写为; 改寫為, to rewrite as)

According to 汉语拼音正词法基本规则 6.1.5.4, the dì (第) used in ordinal numerals is followed by a hyphen: dì-yī (第一, first), dì-356 (第 356, 356th). The hyphen should not be used if the word in which dì (第) and the numeral appear does not refer to an ordinal number in the context. For example: Dìwǔ (第五, a Chinese compound surname).[37][38] The chū (初) in front of numbers one to ten is written together with the number: chūshí (初十, tenth day)

On some occasions, proper nouns can be written in all caps: BĚIJĪNG, GUÓJÌ SHŪDIÀN, GUÓJIĀ YǓYÁN WÉNZÌ GŌNGZUÒ WĚIYUÁNHUÌ

If a proper noun is written together with a common noun to make a proper noun, it is capitalized. If not, it is not capitalized: Fójiào (佛教, Buddhism), Tángcháo (唐朝, Tang dynasty), jīngjù (京剧; 京劇, Beijing opera), chuānxiōng (川芎, Szechuan lovage)

Initialisms

Single words are abbreviated by taking the first letter of each character of the word: Beǐjīng (北京, Beijing) → BJ

A group of words are abbreviated by taking the first letter of each word in the group: guójiā biāozhǔn (国家标准; 國家標準, Guobiao standard) → GB

Initials can also be indicated using full stops: Beǐjīng → B.J., guójiā biāozhǔn → G.B.

When abbreviating names, the surname is written fully (first letter capitalized or in all caps), but only the first letter of each character in the given name is taken, with full stops after each initial: Lǐ Huá (李华; 李華) → Lǐ H. or LǏ H., Zhūgě Kǒngmíng (诸葛孔明; 諸葛孔明) → Zhūgě K. M. or ZHŪGĚ K. M.

Line Wrapping

Words can only be split by the character:guāngmíng (光明, bright) → guāng-míng, not gu-āngmíng

Other idioms are separated according to the words that make up the idiom: bēi hēiguō (背黑锅; 背黑鍋, to be made a scapegoat: "to carry a black pot"), zhǐ xǔ zhōuguān fànghuǒ, bù xǔ bǎixìng diǎndēng (只许州官放火，不许百姓点灯; 只許州官放火，不許百姓點燈, Gods may do what cattle may not: "only the official is allowed to light the fire; the commoners are not allowed to light a lamp")

Many books printed in China use a mix of fonts, with vowels and tone marks rendered in a different font from the surrounding text, tending to give such pinyin texts a typographically ungainly appearance. This style, most likely rooted in early technical limitations, has led many to believe that pinyin's rules call for this practice, e.g. the use of a Latin alpha (ɑ) rather than the standard style (a) found in most fonts, or g often written with a single-story ɡ. The rules of Hanyu Pinyin, however, specify no such practice.[40](3.3.4.1:8)

The first tone (Flat or High Level Tone) is represented by a macron (ˉ) added to the pinyin vowel:

ā ē ī ō ū ǖ Ā Ē Ī Ō Ū Ǖ

The second tone (Rising or High-Rising Tone) is denoted by an acute accent (ˊ):

á é í ó ú ǘ Á É Í Ó Ú Ǘ

The third tone (Falling-Rising or Low Tone) is marked by a caron/háček (ˇ). It is not the rounded breve (˘), though a breve is sometimes substituted due to font limitations.

ǎ ě ǐ ǒ ǔ ǚ Ǎ Ě Ǐ Ǒ Ǔ Ǚ

The fourth tone (Falling or High-Falling Tone) is represented by a grave accent (ˋ):

à è ì ò ù ǜ À È Ì Ò Ù Ǜ

The fifth tone (Neutral Tone) is represented by a normal vowel without any accent mark:

a e i o u ü A E I O U Ü

In dictionaries, neutral tone may be indicated by a dot preceding the syllable; for example, ·ma. When a neutral tone syllable has an alternative pronunciation in another tone, a combination of tone marks may be used: zhī·dào (知道).[41]

These tone marks normally are only used in Mandarin textbooks or in foreign learning texts, but they are essential for correct pronunciation of Mandarin syllables, as exemplified by the following classic example of five characters whose pronunciations differ only in their tones:

The four main tones of Standard Mandarin, pronounced with the syllable ma.

Traditional characters:

媽 (mā)麻 (má)馬 (mǎ)罵 (mà)嗎 (·ma)

Simplified characters:

妈 (mā)麻 (má)马 (mǎ)骂 (mà)吗 (·ma)

The words are "mother", "hemp", "horse", "scold", and a question particle, respectively.

Before the advent of computers, many typewriter fonts did not contain vowels with macron or caron diacritics. Tones were thus represented by placing a tone number at the end of individual syllables. For example, tóng is written tong².
The number used for each tone is as the order listed above, except the neutral tone, which is either not numbered, or given the number 0 or 5, e.g. ma⁵ for 吗／嗎, an interrogative marker.

Briefly, the tone mark should always be placed by the order—a, o, e, i, u, ü, with the only exception being iu, where the tone mark is placed on the u instead. Pinyin tone marks appear primarily above the nucleus of the syllable, for example as in kuài, where k is the initial, u the medial, a the nucleus, and i the coda. The exception is syllabic nasals like /m/, where the nucleus of the syllable is a consonant, the diacritic will be carried by a written dummy vowel.

When the nucleus is /ə/ (written e or o), and there is both a medial and a coda, the nucleus may be dropped from writing. In this case, when the coda is a consonant n or ng, the only vowel left is the medial i, u, or ü, and so this takes the diacritic. However, when the coda is a vowel, it is the coda rather than the medial which takes the diacritic in the absence of a written nucleus. This occurs with syllables ending in -ui (from wei: (wèi → -uì) and in -iu (from you: yòu → -iù.) That is, in the absence of a written nucleus the finals have priority for receiving the tone marker, as long as they are vowels: if not, the medial takes the diacritic.

An algorithm to find the correct vowel letter (when there is more than one) is as follows:[42]

If there is an a or an e, it will take the tone mark

If there is an ou, then the o takes the tone mark

Otherwise, the second vowel takes the tone mark

Worded differently,

If there is an a, e, or o, it will take the tone mark; in the case of ao, the mark goes on the a

Otherwise, the vowels are -iu or -ui, in which case the second vowel takes the tone mark

If the tone is written over an i, the tittle above the i is omitted, as in yī.

The placement of the tone marker, when more than one of the written letters a, e, i, o, and u appears, can also be inferred from the nature of the vowel sound in the medial and final. The rule is that the tone marker goes on the spelled vowel that is not a (near-)semi-vowel. The exception is that, for triphthongs that are spelled with only two vowel letters, both of which are the semi-vowels, the tone marker goes on the second spelled vowel.

Specifically, if the spelling of a diphthong begins with i (as in ia) or u (as in ua), which serves as a near-semi-vowel, this letter does not take the tone marker. Likewise, if the spelling of a diphthong ends with o or u representing a near-semi-vowel (as in ao or ou), this letter does not receive a tone marker. In a triphthong spelled with three of a, e, i, o, and u (with i or u replaced by y or w at the start of a syllable), the first and third letters coincide with near-semi-vowels and hence do not receive the tone marker (as in iao or uai or iou). But if no letter is written to represent a triphthong's middle (non-semi-vowel) sound (as in ui or iu), then the tone marker goes on the final (second) vowel letter.

In spoken Chinese, the third tone is often pronounced as a "half third tone", in which the pitch does not rise. Additionally, when two third tones appear consecutively, such as in 你好 (nǐhǎo, hello), the first syllable is pronounced with the second tone — this is called tone sandhi. In pinyin, words like "hello" are still written with two third tones (nǐhǎo).

An umlaut is placed over the letter u when it occurs after the initials l and n when necessary in order to represent the sound [y]. This is necessary in order to distinguish the front high rounded vowel in lü (e.g. 驴; 驢; 'donkey') from the back high rounded vowel in lu (e.g. 炉; 爐; 'oven'). Tonal markers are added on top of the umlaut, as in lǘ.

However, the ü is not used in the other contexts where it could represent a front high rounded vowel, namely after the letters j, q, x, and y. For example, the sound of the word 鱼/魚 (fish) is transcribed in pinyin simply as yú, not as yǘ. This practice is opposed to Wade–Giles, which always uses ü, and Tongyong Pinyin, which always uses yu. Whereas Wade–Giles needs of using the umlaut to distinguish between chü (pinyin ju) and chu (pinyin zhu), this ambiguity does not arise with pinyin, so the more convenient form ju is used instead of jü. Genuine ambiguities only happen with nu/nü and lu/lü, which are then distinguished by an umlaut.

Many fonts or output methods do not support an umlaut for ü or cannot place tone marks on top of ü. Likewise, using ü in input methods is difficult because it is not present as a simple key on many keyboard layouts. For these reasons v is sometimes used instead by convention. For example, it is common for cellphones to use v instead of ü. Additionally, some stores in China use v instead of ü in the transliteration of their names. The drawback is that there are no tone marks for the letter v.

This also presents a problem in transcribing names for use on passports, affecting people with names that consist of the sound lü or nü, particularly people with the surname 吕 (Lǚ), a fairly common surname, particularly compared to the surnames 陆 (Lù), 鲁 (Lǔ), 卢 (Lú) and 路 (Lù). Previously, the practice varied among different passport issuing offices, with some transcribing as "LV" and "NV" while others used "LU" and "NU". On 10 July 2012, the Ministry of Public Security standardized the practice to use "LYU" and "NYU" in passports.[45][46]

Although nüe written as nue, and lüe written as lue are not ambiguous, nue or lue are not correct according to the rules; nüe and lüe should be used instead. However, some Chinese input methods (e.g. Microsoft Pinyin IME) support both nve/lve (typing v for ü) and nue/lue.

Taiwan (Republic of China) adopted Tongyong Pinyin, a modification of Hanyu Pinyin, as the official romanization system on the national level between October 2002 and January 2009, when it switched to Hanyu Pinyin. Tongyong Pinyin ("common phonetic"), a variant of pinyin developed in Taiwan, was designed to romanize languages and dialects spoken on the island in addition to Mandarin Chinese. The Kuomintang (KMT) party resisted its adoption, preferring the Hanyu Pinyin system used in Mainland China and in general use internationally. Romanization preferences quickly became associated with issues of national identity. Preferences split along party lines: the KMT and its affiliated parties in the pan-blue coalition supported the use of Hanyu Pinyin while the Democratic Progressive Party and its affiliated parties in the pan-green coalition favored the use of Tongyong Pinyin.

Tongyong Pinyin was made the official system in an administrative order that allowed its adoption by local governments to be voluntary. A few localities with governments controlled by the KMT, most notably Taipei, Hsinchu, and Kinmen County, overrode the order and converted to Hanyu Pinyin before the January 1, 2009 national-level switch,[4][5] though with a slightly different capitalization convention than mainland China. Most areas of Taiwan adopted Tongyong Pinyin, consistent with the national policy. After 2009 switch, many street signs in Taiwan today still display Tongyong Pinyin but some, especially in northern Taiwan, display Hanyu Pinyin. It is still not unusual to see spellings on street signs and buildings derived from the older Wade–Giles, MPS2 and other systems.

The adoption of Hanyu Pinyin as the official romanization system in Taiwan does not preclude the official retention of earlier spellings. International familiarity has led to the retention of the spelling Taipei ("Taibei" in pinyin systems) and even to its continuation in the name of New Taipei, a municipality created in 2010. Personal names on Taiwanese passports honor the choices of Taiwanese citizens, who often prefer the Wade–Giles romanization of their personal names, though the official online conversion tool lists pinyin before other systems. Transition to Hanyu Pinyin in official use is also necessarily gradual. Universities and other government entities retain earlier spellings in long-established names, and budget restraints preclude widespread replacement of signage and stationery in every area. Primary education in Taiwan continues to teach pronunciation using zhuyin (MPS or Mandarin Phonetic Symbols).

Pinyin is now used by foreign students learning Chinese as a second language.

Pinyin assigns some Latin letters sound values which are quite different from that of most languages. This has drawn some criticism as it may lead to confusion when uninformed speakers apply either native or English assumed pronunciations to words. However, this problem is not limited only to pinyin, since many languages that use the Latin alphabet natively also assign different values to the same letters. A recent study on Chinese writing and literacy concluded, "By and large, pinyin represents the Chinese sounds better than the Wade–Giles system, and does so with fewer extra marks."[47]

Because Pinyin is purely a representation of the sounds of Mandarin, it completely lacks the semantic cues and contexts inherent in Chinese characters. Pinyin is also unsuitable for transcribing some Chinese spoken languages other than Mandarin, languages which by contrast have traditionally been written with Han characters allowing for written communication which, by its unified semanto-phonetic orthography, could theoretically be readable in any of the various vernaculars of Chinese where a phonetic script would have only localized utility.

Simple computer systems, able to display only 7-bit ASCII text (essentially the 26 Latin letters, 10 digits, and punctuation marks), long provided a convincing argument for using unaccented pinyin instead of Chinese characters. Today, however, most computer systems are able to display characters from Chinese and many other writing systems as well, and have them entered with a Latin keyboard using an input method editor. Alternatively, some PDAs, tablet computers, and digitizing tablets allow users to input characters graphically by writing with a stylus, with concurrent online handwriting recognition.

In addition, in accordance to the Regulation of Phonetic Transcription in Hanyu Pinyin Letters of Place Names in Minority Nationality Languages (少数民族语地名汉语拼音字母音译转写法; 少數民族語地名漢語拼音字母音譯寫法) promulgated in 1976, place names in non-Han languages like Mongolian, Uyghur, and Tibetan are also officially transcribed using pinyin in a system adopted by the State Administration of Surveying and Mapping and Geographical Names Committee known as SASM/GNC romanization. The pinyin letters (26 Roman letters, plus ü and ê) are used to approximate the non-Han language in question as closely as possible. This results in spellings that are different from both the customary spelling of the place name, and the pinyin spelling of the name in Chinese:

^The online version of the canonical[clarification needed "According to which group?"]Guoyu Cidian (《國語辭典》) defines this term as: 標語音﹑不標語義的符號系統，足以明確紀錄某一種語言。 'a system of symbols for notation of the sounds of words, rather than for their meanings, that is sufficient to accurately record some language'. See this entry online.[permanent dead link] Retrieved 14 September 2012.

^Rohsenow, John S. 1989. Fifty years of script and written language reform in the PRC: the genesis of the language law of 2001. In Zhou Minglang and Sun Hongkai, eds. Language Policy in the People's Republic of China: Theory and Practice Since 1949, p. 23